This invention relates to electronic flash systems and more particularly to an electronic flash system which controls the size of the aperture in a photographic objective lens on the basis of aperture information provided by a computer type electronic flash device.
When the aperture value set on the flash device is coincident with that set on the camera, i.e. the aperture size of a diaphragm in the photographic objective lens, a correct flash exposure can be automatically obtained. Even with such a system, however, photographers unaccustomed to flash photography are liable to choose an aperture value for the flash device which never coincides with aperture values available for the interchangeable objective lens being used, i.e. apertures which are beyond the dynamic range of diaphragm control of the objective lens. Because different lenses have different F-numbers at the greatest aperture opening, there are situations where changing lenses makes it impossible to obtain a correct exposure.
It is an object of the present invention to provide an electronic flash system which overcomes the above-described drawback of the conventional system.
This and other objects of the present invention will become apparent from the following detained description of an embodiment thereof.